Underfeed stoker



(No Model.) 2 Sheets-She'et 1.

- D. P. GRAHAM.

UNDERFEBD STOKER.

No. 570,924. Patented Nov. 1-0, 1896.

NORRIS 9:755; 00 wow-mum WASHINGTO 2 Sheets-Sheet (.No Model.)

1). FGRAHAM. UNDERFEBD STOKER.

No. s70,924. Patented Nov. 10, 18.96.

1| ft" MT '1 w vbweooeo DRRIS PETERS co.moTo-\.mo.. WASHINGTON u c UNITED STATES PATENT OFFICE.

DAVID F. GRAHAM, OF SP RINGFIELD, MASSACHUSETTS, ASSIGNOR TOTHE AMERICAN STOKER COMPANY, OF DAYTON, OHIO.

UNDERFEEDSTOKER.

SPECIFICATION forming part of Letters Patent No. 570,924, dated November 10, 1896.

Application filed October 28, 1895. Serial No. 567,134. (No model.)

To all whom it may concern; magazine and hopper being connected by a Be it known that I, DAVID F. GRAHAM, a pipe or conduit through which there is excitizenoftheUnited States,residingat Springtended a worm conveyer. This worm con- 55 field,in the county of I-Iampden and State of veyer is made of a uniform carrying capacity Massachusetts, have invented certain new from the hopper through the pipe or conduit, 7 and useful Improvements in Underfeed and within the magazine the carrying capac- Stokers, of which the following is a specifiity of the magazine is reduced, so that a porcation. tion only of the fuel which is carried into said 60 My invention relates to devices for feeding magazine will be conveyed through the same. fuel into furnaces, the constructions being A part ofthe fuel, therefore, will be forced especially adapted for feeding furnaces for upwardly and an equal distribution thereof steam-boilers, although the same constructakes place within the magazine. tions are applicable for feeding furnaces of In the said drawings, a represents ahopper, 65 any kind. and a the fuel-magazine. a is a pipe or con- The object of my invention is to provide duit which connects the same.

means for readily feeding coal or similar fuel 0 is a conveyer the flights of which are from the outside of a furnace into the intepreferably mounted on a square shaft '0, rior thereof, so that the coal or other fuel will which is journaled at each end in suitable 70 be fed from the bottom of the furnace and bearings and has at the outside means for ro-' from beneath the fire. V tating the same, any suitable means being My invention consists in the various conemployed for this purpose. g structions and combinations of parts herein- As shown 1n Flg. 1, the reduced carrying after described, and set forth in the claims. capacity of the conveyer is accomplished by 75 In the accompanying drawings, Figure 1 is reducing the diameter of the conveyer; that 2 5 a vertical longitudinal sectional view of a deis, reducing the width of the conveyer-flights, vice embodying my invention. Fig. 2 is a as shown at c 0 I have also reduced the transverse section of the same. Fig. 3 is a number of flights. While the pitch of the similar view to Fig. 1 showing a modification. conveyer remains the same, the reduction in 80 Fig. 4 is a partial plan view of the construcdiameter will cause a less carrying capacity, 0 tion shown in Fig. 3. Fig. 5 is a sectional and the coal or other fuel which is supplied elevation showing a" further modification. to the magazine through the conduit by the Like parts are represented by similar letconveyer. which has a uniform carrying caters of reference in the several views. pacity will be distributed along the maga- 8- In constructing stokers for furnaces, eszine by the fact that only a portion of the I 5 pecially furnaces for steam-boilers, it is desame will be carried through the magazine sirable that the constructions be such that by the conveyer of reduced carrying capacity. they may be applied to furnaces already in The balance of the fuel, therefore, will necesuse, and to this end the parts thereof should sarily be forced upward by the incoming 0 be kept within as small compass as possible, fuel and will be distributed along the magaand especially this is true of the parts which zine and into the furnace. If desired, this lead from the outside to the inside of the f urcarrying capacity may be still further renace and which carry the fuel therein. It duced and a more uniform distribution seis also desirable that means be employed by cured by reversing some of the conveyer- 5 which the fuel may be uniformly fed into the flights, as shown at 0 that is to say, employfurnace continuously, if so desired, the coning conveyer-flights of a reverse pitch, which structions being such that an equal distribuwill hold back the fuel brought in the contion of the fuel into the fire-box or magazine veyer through the conduit, and thus cause the may be effected. In carrying out this feasame to rise in the conduit. J00 ture of my invention I employ within the In Figs. 3 and 41 have shown substantially 5o furnace, with the top preferably located flush thev same construction, with the exception with the grate-bars thereof, a magazine, and thatthe conveyer is formed tapered throughon the outside thereof I employ a hopper, the out themagazine, as shown at 0 the diame- A ter of the conveyer being gradually reduced from one end of the magazine to the other, while the pitch of the conveyer remains the same. I r

In Fig. 5 I have shown means for accomplishing the same result by reducing the pitch of the conveyer within .the magazine, as shown at 0 In this case the diameter of the conveyer is uniform throughout and the pitch thereof is uniform in the hopper and through the conduit; but that portion of the conveyer which is placed within the magazine is formed with a reduced carrying capacity by gradually reducing the pitch, so that a portion only of the fuel which is brought in through the conduit is carried through the magazine, the remainder of the fuel being distributed along the magazine and forced upwardly by the incoming fuel, so as to form an even distribution at the top of the magazine.

The magazine will be provided in the usual way with twyer-blocks d at the top thereof, to which air is supplied from any suitable source of supply through suitable air-pipes d. The magazine is preferably formed of a length equal to the length of the grate-bars and is of a uniform width throughout. It is curved at the bottom to correspond to the conveyer, which passes through the same and forms substantially a continuation of the conduit, open at the top, the upper portion of the magazine being formed with inclined or sloping sides, so that the area of the magazine in cross-section is increased from the bottom upwardly.

By the constructions above describedit will be seen that I have provided a stoker which may be readily installed in furnaces now in use. The conduit being formed of a straight horizontal pipe of, say, eight inches in diameter, can be readily introduced through the front of any ordinary furnace, an opening of sufficient size being made therein to receive the same. The hopper is placed on the outside of the furnace in convenient position to receive the fuel, and means being provided to'revolve the conveyer, the fuel is carried uniformly and, if desired, continuously into the magazine by the conveyer of uniform carrying capacity, where it is distributed by that portion of the conveyer within the magazine which is formed with a reduced carrying capacity.

Having thus described my invention, I claim 1. The combination with a f uel-magazine having a curved bottom, and a conduit leading laterally therefrom, said conduit consisting of a pipe of uniform diameter whose axis corresponds to the axis of the curved portion of the magazine, a hopper connected with said conduit, and a screw conveyer extending from said hopper centrally through said conduit into said magazine, said conveyer being formed of a uniform carrying capacity within said conduit and of a reduced carrying capacity within the magazine, substantially as specified.

2. The combination with a magazine,afuelhopper, and ahorizontal conduit, as described, said conduit being of a uniform diameter and located between the hopper and magazine so as to form a substantial continuation of the bottom of each, a screw conveyer extending from said hopper through said conduit into said magazine and adapted to fit said conduit, said conveyer being provided with a uniform carrying capacity through the conduit and of a reduced carrying capacity in the magazine, substantially as specified.

3. The combination with a fuel-magazine having a curved bottom and tapered sides, a conduit leading horizontally from said magazine and consisting of a pipe whose axis also forms the axis of the curved portion of said magazine, said conduit being of a uniform diameter and cut away on one side near its outer end to form a fuel-opening, and a hopper above said fuel-opening, ascrew conveyer extending through said conduit and the curved portion of said magazine, said conveyer being. formed of a uniform carrying capacity through said conduit and adapted to fit the same, and of a reduced carrying capacity within the bottom portion of said magazine, substantially as specified.

4. The combination with a fuel-magazine having a curved bottom, and a conduit leading laterally therefrom, said conduit consisting of a pipe of uniform diameter whose axis corresponds with the axis of the curved portion of said magazine, a hopper connected with said conduit, and a screw conveyer extending from said hopper centrally through said conduit into said magazine, said conveyerbeing formed of a uniform diameter and pitch within said hopper and conduit, and be ing tapered to form a gradually-reduced diameter within the magazine, substantially as specified.

5. The combination with a magazine con structed of a substantially uniform width and having tapered sides and a concave bottom as described, a horizontal conduit leading from one end of said magazine, and a hopper arranged above said conduit so as to discharge therein, a square shaft extending centrally through said conduit and magazine, the bottom of said magazine forming a substantial continuation of said conduit, and conveyerflights on said shaft, said conveyer-flights being formed to fit said conduit and having a uniform carrying capacity within the same and a reduced carrying capacity within the magazine, substantially as specified.

In testimony whereof I have hereunto set my hand this 21st day of September, A. D. 1895.

DAVID F. GRAHAM.

\Vitnesses:

WM. P. HAYES, EDWIN D. BEVITT. 

